About 60 percent of the 4,000 websites advertising relief services for Hurricane Katrina are based abroad, and many of them as well as those based in the U.S. could be fake, the FBI said Tuesday, reports Reuters. Senior FBI and Justice Department officials warned donors to be cautious and avoid fraudulent charities, including those pretending to be major organizations such as the Red Cross.

U.S. Attorney General Alberto Gonzales said some of the bogus sites had been shut down but would not give details. The Red Cross has hired a security company to scan for phishers attempting to gain access to credit card numbers and personal information on sites that imitate the Red Cross's.